The present invention relates to a track system, and more particularly to improvements on my U.S. Pat. No. 5,735,214, issued Apr. 7, 1998, entitled Streamline Track System with Carriers and Rail.
In the above-mentioned U.S. Patent, at least one carrier equipped with roller assemblies is adapted to run along a straight and/or curving guide rail either by outside driving means or automatically by self-driving means.
The guide rail has a pair of opposed parallel guide sides and a pair of opposed parallel set sides. Each of the guide sides is provided with a pair of parallel plain lanes and a V edge protruded between the pair of parallel plain lanes. The V edge has a top portion and a base portion. The guide rail is fixed to a supporting structure with set bolts through the set sides either directly or by the intermediary of at least one base member.
The carrier has a frame and a plurality of roller assemblies secured to the frame for supporting the carrier by engaging with the opposed parallel guide sides. Each of the roller assemblies comprises a journal and a pair of ball bearings mounted on the journal with a space left between the pair of ball bearings. Each of the pair of ball bearings includes an outer race which engages with each of the pair of parallel plain lanes and which has a beveled corner facing to the V edge. Each of the pair of ball bearings is adapted to cooperate with the V edge such that the beveled corner engages with the V edge base portion, and such that the V edge top portion remains in the space between the pair of ball bearings without engaging the outer race.
Thus the carrier is adapted to run along the guide rail not only by the engagement of the V edge base portion and the ball bearing beveled corners but also by the engagement of the parallel plain lanes and the ball bearing outer races except the beveled corners, while the V edge top portion remains free of engagement, at each of the guide sides of the guide rail.
In case the guide rail is a streamline which has a plurality of straight and curving rail segments connected with each other, each of the curving rail segments comprises a curving middle part and straight extensions formed at both ends of the curving middle part. These straight extensions are connected with straight rail segments or similarly formed straight extensions of other curving rail segments. Thus the guide rail has no straight-to-curving joint but straight-to-straight joints only, though it includes both straight and curving rail segments.
In case the carrier is adapted to run automatically by self-driving means, the guide rail is fixed to a supporting structure by the intermediary of base members, and a gear rack is provided at one side of the base members along one of the guide sides. A motor with a drive shaft is mounted on the carrier frame. A pinion is connected to the drive shaft and adapted to engage with the gear rack. Thus the carrier runs automatically along the guide rail as the motor drives the pinion in engagement with the gear rack.
It can be said that the above-described automatic running system has an outstanding advantage that there is no need of providing outside driving means which may include chains, belts, rods or screws all along the guide rail, thus not only saving cost and space but also facilitating installation and minimizing maintenance. This advantage is especially great in case the guide rail is such a streamline as includes a plurality of various curving rail segments.
However, a streamline guide rail for a self-driving carrier will require a streamline gear rack just suitable to be combined with the guide rail. And it is desired that this streamline gear rack is not only accurate, strong, durable, stable, noiseless, light and compact, but also easy and cost-saving to manufacture, install, operate and maintain, whatever curvature and length it may have on one plane. It is even desired that the gear rack can be combined with a guide rail having a three-dimensional running direction.